Optical fiber connector and ferrule

ABSTRACT

Multi-fiber ferrules may be produced with tapered bodies and guide pin holes that have fluted internal surfaces with projections for engaging the guide pins, and channels for capturing any foreign material that may accumulate on or around the guide pins, thereby providing improved consistency in fiber connections during mating of the ferrules.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/056,100 filed Feb. 29, 2016, which is a continuation of U.S. patentapplication Ser. No. 14/276,999 filed May 13, 2014, now U.S. Pat. No.9,274,287 issued Mar. 1, 2016, both of which are incorporated herein byreference in their entirety.

BACKGROUND

Optical ferrules which are standardized according to JIS C 5981, IEC61754-5 and the like, are called MT (Mechanically Transferable)ferrules, and are used for connecting optical fibers. MT ferrulesgenerally use at least two guide pins for high-accuracy positioning ofeach optical fiber in the ferrule. An MT ferrule body may include twoguide pin holes on the end surface of the ferrule for receiving theguide pins therein, and may have a plurality of optical fiber holes forreceiving the optical fibers. The respective optical fibers may beinserted into the optical fiber insertion holes from a rear end of theMT ferrule, and may be fixed in place with adhesive.

An adapter may be used for face-to face joining of two MT ferrules. MTferrules generally have a rectangular cross-sectional shape, andlikewise, the adapter may be in the shape of a rectangular cylinder forinsertion of one ferrule into each end. Two MT ferrules, one with guidepins installed (male connector) and one without guide pins (femaleconnector) are inserted into opposite ends of the adapter whereby theferrules are aligned together with one another as the male guide pinsenter the female guide pin holes. One type of connector that uses MTferrules is an MPO (multi-fiber push-on) connector

The MT ferrules get pushed together within the adapter to opticallyconnect the ferrules by means of a so-called PC (Physical Contact)connection, wherein the optical fibers in one ferrule contact theoptical fibers in the other ferrule and get compressed together toprovide an optical connection. Optical transmission performance betweenthe optical fibers is strongly dependent on connecting conditions suchas axis alignment and inclination of the optical fibers, and gapsbetween the opposing optical fibers.

To prevent gaps during connection, it is necessary to remove foreignmaterials that may be adhered to the connection end face of the MTferrule. Any foreign materials are commonly wiped off by use of acleaner. However, connection loss at the PC connection may be increasedduring wiping off, because some of the foreign materials may be gatheredand deposited around base portions of the guide pins. In general, anyforeign materials that may be present on the end face or components ofthe end face may interfere with the connection by causing the faces tobe spaced apart from one another, resulting in gaps between the opticalfibers.

In addition, in installations wherein the adapter is fixedly mounted ina panel, for example, the angular orientation of the ferrule as it isretrieved, aligned, and inserted may stress the optical fibers, andpossibly result in breakage of a fiber or fibers if considerable care isnot taken when the ferrule is inserted into the adapter.

Therefore, during the mating of MT ferrules, there remains a need forminimization of issues that may result in poor fiber mating connections,such as contamination on the end faces of the MT/MPO ferrules, and thepossibility of fibers breaking when the MPO connector is inserted intoan MPO adapter in a rough or incorrect manner.

SUMMARY

Modifications of the MT ferrules may provide for better fiberconnections during mating of the ferrules. To reduce the accumulation ofcontaminants on or between faces of mating ferrules, channels may beprovided within the guide pin holes for debris accumulation. Inaddition, to reduce the possibility of breaking fibers while inserting aferrule into an adapter, the ferrule body may be provided with a tapereddesign to allow for some initial play and leeway during the initialstage of the insertion into the adapter.

In an embodiment an optical fiber connector is disclosed. The connectoris configured for being coupled with an adapter to mate with anotheroptical fiber connector, and the connector includes a housing having afirst end for being coupled with the adapter, and a ferrule floatablymounted in the housing. The housing defines a first longitudinal passagetherethrough, with the first longitudinal passage defining a firstlongitudinal axis. The ferrule is floatably mounted at the first housingend within the first longitudinal passage for relative movement betweenthe ferrule and the housing, and the ferrule includes a first endprotruding forward of the first housing end, and a second end spacedfrom the first end and disposed within the first longitudinal passage,the ferrule defining a second longitudinal axis extending from the firstend to the second end, and the first end includes an end face for matingwith an end face of an additional ferrule. The ferrule includes at leastfirst and second alignment pin holes in the end face configured forreceiving an alignment pin therein, wherein each of the first and secondalignment pin holes have a longitudinal direction parallel with thesecond longitudinal axis, and each pin hole defines an interior surfacecomprising a plurality of spaced apart longitudinal grooves extendingfrom the end face and into the ferrule. The ferrule also includes atleast one side wall having a first wall end at the end face andextending from the end face to a second wall end adjacent the second endof the ferrule, with the at least one side wall tapering outwardly awayfrom the second longitudinal axis in a direction from the end facetowards the second end so that the ferrule is tiltable within thehousing passage to offset the second longitudinal axis with respect tothe first longitudinal axis.

In an embodiment, an optical ferrule includes a housing that includes afirst end, a second end spaced from the first end, and a longitudinalaxis extending from the first end to the second end, wherein the firstend comprises an end face for mating with an end face of an additionaloptical ferrule. The housing also includes at least one passageextending through the housing and configured for receiving at least oneoptical fiber therein for termination of the at least one optical fiberat the end face, and at least one side wall extending from the end facetowards the second end, the at least one side wall tapering outwardlyaway from the longitudinal axis in a direction from the second end tothe first end.

In an embodiment, an optical ferrule includes a housing that includes afirst end, a second end spaced from the first end, and a longitudinalaxis extending from the first end to the second end, wherein the firstend comprises an end face for mating with an end face of an additionaloptical ferrule. The housing also includes at least one passageextending through the housing and configured for receiving at least oneoptical fiber therein for termination of the at least one optical fiberat the end face, and at least first and second alignment pin holes inthe end face configured for receiving an alignment pin therein, each ofthe first and second alignment pin holes having a longitudinal directionparallel with the longitudinal axis, and defining an interior surfacecomprising a plurality of spaced apart longitudinal grooves extendingfrom the end face and into the housing.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A and 1B depict a tapered ferrule body with modified guide pinholes according to an embodiment.

FIGS. 2A and 2B depict a non-tapered ferrule body with modified guidepin holes according to an embodiment.

FIGS. 3, 3A, 3B and 3C depict various views of the ferrule of FIGS. 1Aand 1B according to an embodiment.

FIGS. 4, 4A, 4B and 4C depict various views of the ferrule of FIGS. 2Aand 2B according to an embodiment.

FIG. 5 provides a representative illustration of the mating of twoferrules having non-tapered bodies according to an embodiment.

FIG. 6 provides a mated depiction of two tapered body ferrules accordingto an embodiment.

FIGS. 7A and 7B provide a top view of a mated connection of tapered-bodyferrules according to an embodiment.

FIGS. 8A and 8B provide a side view of a mated connection oftapered-body ferrules according to an embodiment.

FIG. 8C provides a representative illustration of engagement surfaces ofa flange and housing shoulder according to an embodiment.

FIGS. 9A and 9B provide a top view of a representative illustration ofthe angular insertion variability provided by a tapered ferrule bodyaccording to an embodiment.

FIGS. 10A and 10B provide a side view of a representative illustrationof the angular insertion variability provided by a tapered ferrule bodyaccording to an embodiment.

FIGS. 11A and 11B provide a comparative illustration of the insertionrigidity provided by a non-tapered ferrule body.

FIGS. 12A and 12B provide end views along line X of FIG. 5 of matedferrule bodies according to an embodiment.

FIGS. 13A, 13B and 13C provide a detailed cross-sectional view of themating of two ferrule bodies and the avoidance of contaminant blockageaccording to an embodiment.

FIG. 14 depicts an alternative configuration for the guide pin holesaccording to an embodiment.

DETAILED DESCRIPTION

While the following description is directed towards MT optical ferrules,the embodiments described may be applicable to other ferrule types aswell. As represented in the embodiments of FIGS. 1A, 1B, 2A and 2B, aferrule may have a main body 110 or 210 that defines a front, insertionend 112 or 212, that may be inserted into an adaptor 9 (shown in outlinein FIG. 5), as well as a rear end 114 or 214. The rear end may typicallybe engaged in or with a fiber optic connector housing (not shown). In anembodiment as represented in FIGS. 1A and 1B, the ferrule body 110 maybe a tapered-body, as shown in greater detail in FIGS. 3, 3A, 3B and 3C,and may have a frusto-pyramidal shape, or define a rectangular frustum.In an alternative embodiment, as represented in FIGS. 2A and 2B, theferrule body 210 may be cuboid with essentially parallel opposing faces,as shown in greater detail in FIGS. 4, 4A, 4B and 4C.

The rear end 114 or 214 may include an opening 11 configured forreceiving an end of a multi-fiber optical cable 13, that may be, forexample, a ribbon cable of a plurality of individual optical fibers 15.The front end 112 or 212 may have a connection end face 116 or 216 thatmay include a plurality of optical fiber insertion holes 17 arranged inat least one row, or as shown, two rows. Individual ones of the opticalfibers 15 of the multi-fiber cable 13 may be disposed in the holes 17 toterminate at the connection end face 116, 216.

In an embodiment, the front end 112, 212 of the ferrule body 110, 210may be formed to have a rectangular cross-sectional shape. The rear end114, 214 of the ferrule main body 110, 210 may be provided with a flange19. The optical fibers 15 may be inserted, via the opening 11, throughthe flange 19, and into the optical fiber insertion holes 17. A top face118, 218 of the insertion end 112, 212 may include an access opening 21for guiding the optical fibers 15 into the holes 17. The optical fibers15 may be fixed in place by use of an adhesive that may be injected intothe ferrule body 110, 210 via the access opening 21 and/or the cableopening 11.

Guide pin insertion holes 25, described in greater detail below, may beprovided through the body 110, 210, extending from the connection endface 116, 216 out through the rear end 114, 214. In an alternativeembodiment, guide pin insertion holes 25 may be configured only at thefront ends 112, 212. Guide pins, such as guide pins 27 shown in FIG. 5,may be inserted into the guide pin holes 25 for precise alignment of apair of ferrules as shown in FIGS. 5 and 6.

FIG. 3 shows a top plan view of the tapered-body ferrule 110, and FIG.3A shows a side view. In an embodiment, a ferrule 110 may have at leastone side wall having a first wall end at the connection face 116 andextending from the connection face to a second wall end adjacent therear end 114 of the ferrule. The at least one side wall may taperoutwardly away from a longitudinal axis of the ferrule in a directionfrom the connection face 116 towards the rear end 114.

In an embodiment, the at least one side wall may include a top face 118,bottom face 120, and side faces 122, and the faces may each taperoutwardly in a direction from the connection face 116 towards the rearend 114. The use of ‘top’, ‘bottom’ and ‘side’ are provided forreference only and are relative to the figures, wherein the figurescould have essentially been drawn with any orientation showing any ofthe faces 118, 120 or 122 as the ‘top’ for example. As depicted, faces118 and 120 are opposite one another, and faces 122 are opposite oneanother and orthogonal to faces 118 and 120.

The flange 19 extends laterally away from the top face 118, bottom face120, and side faces 122. A reference line 130 orthogonal to the flange19 is also shown. In an embodiment, as shown, the side faces 122 may bedisposed at an angle α from the orthogonal, and the top face 118 andbottom face 120 may be disposed at an angle β. In an embodiment, theangles α and β may be the same. In various embodiments, the angles α andβ may have a value of about 1°, about 1.5°, about 2°, about 2.5°, about3°, about 3.5°, about 4°, about 4.5°, and about 5°, and any valuebetween any of the listed values. In an embodiment as represented byFIGS. 3 and 3A, the angles α and β may be about 3°. The amount ofangular taper may be limited essentially only by design. For example, itmay be desirable for the tapered sides to remain external to the guidepin holes 25.

In alternative embodiments, the angles α and β may be different from oneanother, or in further embodiments, each of the side faces 122 may bedisposed at different angles α, and the top face 118 and bottom face 120may be disposed at different angles β. Due to the angular taper, thecross-sectional area of the ferrule body at the connection face 116 isless than a second cross-sectional area adjacent the flange 19, and theflange has a third cross-sectional area that is greater than the secondcross-sectional area.

FIGS. 7A, 7B, 8A, and 8B, provide a representation of a panel structure300 with mated ferrules 110 a, 110 b. Each of the ferrules 110 a, 110 bmay be a component of an optical fiber connector assembly 302 a, 302 bwith some parts represented schematically. An adaptor 9, as alsorepresented in FIG. 5, may be mounted with the panel 300 and may beconfigured for receiving the connector assemblies 302 a, 302 b, viaopposing openings 9 a and 9 h, into a longitudinal passage 9 c. Theadaptor 9 may define a first longitudinal axis 9 d.

Each of the connector assemblies 302 a, 302 b may include a housing 304that define an internal passage 305, and a second longitudinal axis 305d. The first longitudinal axis 9 d and the second longitudinal axis 305d may generally be parallel when no external lateral forces are appliedto a connector assembly 302 a, 302 b. The ferrules 110 a, 110 b may beconfigured so that the front ends 112 a, 112 b extend out of connectorassemblies 302 a, 302 b for mating of the connection end faces. Guidepins 27 may be provided as components of a pin block 308 that may beinserted through guide pin holes 25 through the back end 114 of aferrule body to extend forwardly of the connection end face 116 to enterinto guide pin holes 25 of the opposing mating ferrule body.

A biasing force for maintaining the ferrule 110 a, 110 b in engagementwith one another may be provided by a biasing member, such as a spring310 and spring retainer 312. The spring 310 may be compressed betweenthe pin block 308 and the spring retainer 312 to bias the pin block awayfrom the retainer and forwardly through the connector housing 304 forengagement with the opposing ferrule. The ferrules 110 a, 110 b may beretained within the connector housings 304 by configuring the flange 19to have a dimension that is greater than an internal dimension definedbetween the shoulders 320. The flange 19 may be biased into engagementwith the shoulder 320. Similarly, the housing 304 may be retained withinthe adaptor 9 by providing an engagement projection 322 on the exteriorof the housing and an engagement shoulder 324 internally within theadaptor so that the engagement projections define an external dimensionthat is greater than an internal dimension defined between theengagement shoulders 324.

With an embodiment as shown and described, the tapered body ferrules 110a, 110 b, are configured as ‘floating’ ferrules and may be floatablymounted within their respective housings 304, wherein the ferrule andhousing are movable relative to one another, so that the ferrule maytilt through a conical range of movement within the housing. In anembodiment as illustrated in FIG. 7B, housing 304 may be displacedlaterally relative to the ferrule 110 b so that the longitudinal axis305 d moves through an angle of about θ₁ with respect to thelongitudinal axis 9 d. In an embodiment, the angle θ₁ may be an amountapproximately the same as the previously described angle α.

Application of a lateral force F, for example, may therefore cause thehousing 304 to mover relative to the mated ferrules, thereby reducingpossible breakage of a connector 302 a, 302 b, and allowing for themated connection surfaces to remain aligned and mated within the adaptor9. In an embodiment, a stop 330 may be provided to prohibit movementbeyond the maximum displacement angle θ₁, thereby reducing potentialdamage to a ferrule. A multifiber connector 302 may be designed suchthat the clearances between the inner sidewalls 305 of the connectorhousing 304 and the tapered ferrule sides are increased in a mannerwhich maintains the alignment of the ferrule relative to the connectorhousing, while at the same time permitting the ferrule to freely floatwithin the connector housing as lateral forces are applied to themultifiber connector, thereby maintaining low optical attenuation aslateral forces are applied. In particular, it has been determined thatthe clearance between the inner sidewalls of the connector housing andthe forward end of the ferrule are particularly critical to the freedomwith which a ferrule floats within the connector housing as themultifiber connector is subjected to lateral forces. In an additionalembodiment, not shown, the side walls 305 may also taper outwardly fromthe shoulder 320 towards the front end 306 to provide additionalrelative angular movement between the housing 304 and the ferrule 110.

FIGS. 8A and 8B provide a similar depiction to the illustrations ofFIGS. 7A and 7B except from a side view of the mated ferrules 110 a, 110b. In a similar manner as discussed, the connector housing 304 may moveup and down relative to the ferrule through an angle θ₂. In anembodiment, the angle θ₂ may be an amount approximately the same as thepreviously described angle β.

As represented in FIG. 8C, in an alternative embodiment of theengagement surfaces of flange 19 and shoulder 320, one or both of thesurfaces 19 a of the flange and surface 320 a of the housing shoulder,may be angled. As such, under the bias applied by the spring 310 theferrule 110 may self-center within the internal passage of the housing.For comparison, FIG. 7B depicts an embodiment having squared shouldersfor the engagement surfaces of flange 19 and shoulder 320, and FIG. 8Bdepicts an embodiment having an angled surface for the engagementsurfaces of flange 19 and a squared shoulder 320.

In an alternative embodiment, as represented in FIGS. 9A and 10A, byproviding the body 110 with tapered faces, a degree of angular freedommay be provided during insertion of the ferrule into an adaptor 9. FIG.9A shows a representative top/bottom view of a ferrule body 110 after apartial insertion into an adaptor 9, while FIG. 10A shows arepresentative side view. The representations of FIGS. 9A and 10A areprovided as examples only, to illustrate an approximation of the angularleeway during an insertion, and other variants and configurations mayalso be provided. In comparison, FIG. 11 depicts the insertion of theferrule body 210 (rectangular-cuboid or non-tapered, insertion end) intoan adaptor 9.

Prior to insertion of a ferrule into an adaptor, with no obstacles nearthe opening of the adaptor, there might be essentially angular freedomof movement within approximately hemispherical confines as the ferruleis brought into the vicinity of the adaptor. However, as shown in FIG.11, after a partial insertion of the cuboid housing 210 into the adaptor9, there is essentially no remaining angular freedom of movement for theferrule body within the adaptor, thus requiring there to be essentiallycompletely unrestricted access directly in front of the adaptor 9 for astraight-in insertion. If a forced bending is required during insertion,strain may be applied to the other components of an MPO connectorcontaining the MT ferrule, and damage, or a reduction in the quality ofthe connection, may result. For example, the MPO fibers may break if theMPO connector is forcibly bent for insertion into the adaptor 9.

As shown in FIGS. 9A and 10A, however, if the insertion end 112 istapered, the ferrule may still be movable side-to side (FIG. 9A) withinan angular displacement of about θ₁ and may still also movableup-and-down (FIG. 9B) within an angular displacement of about θ₂. Thevalues for θ₁ and θ₂ may be the same, or may be different. The extent ofθ₁ and θ₂ may vary based on the taper angle of the sides, as well as theinternal configuration within the opening of the adaptor 9. For example,in an embodiment as shown in FIGS. 9A and 10A, portion 140 a and 141 a,and portions 142 a and 143 a of the internal guide walls adjacent theopening may be parallel to provide a larger internal cavity adjacent theopening at least for about one-half of the insertion length. Theremaining portion of the guide walls 140 b and 141 b, and portions 142 band 143 b may be tapered to provide alignment of the ferrule body 110into its final seated position (shown in FIGS. 9B and 10B). Otherinternal configurations may also be provided.

In an embodiment as depicted in FIG. 6, ferrule housings 110 withtapered bodies may include cylindrical guide pin holes 25. To providefor an improved face-to-face connection of connection surfaces 116, 216,(as shown for example in FIGS. 6 and 13C), the connection surfacesshould be free of foreign material that may inhibit contact between thesurfaces and the optical fibers terminated therein. One area in which anaccumulation of foreign material may result is at the base of the guidepins 27 (see for example 60-1 in FIG. 13A). For example, the foreignmaterial may accumulate here in the formed ‘corner’ when the connectionsurface is wiped. Also, In order to attain precise alignment offerrules, very little tolerance is provided between the externaldiameter of the guide pins 27 and the internal diameter of the guide pinholes 25. As such, if any foreign debris is present on the guide pin 27the debris may be pushed along the pin as the pin is inserted into thepin hole 25 so that the debris remains as an accumulation at the base ofthe pin on the surface 116, 216. This accumulation may prevent propercontact between adjoining contact surfaces and thereby result in a poortransmission between ferrules.

One manner in which to inhibit an accumulation of foreign material atthe base of the pins 27 from being a hindrance to good surface contactbetween surfaces 116, or surfaces 216 may include providing a flutedinternal surfaces within the pin holes 25, or providing a plurality oflongitudinal grooves along the internal surface of the pin holes. In anembodiment as shown in FIGS. 3B, 3C, 4B and 4D, for example, andenlarged detail in FIG. 12, guide pin holes 25 may include at leastthree raised ridges 50-1, 50-2 and 50-3, offset circumferentially fromone another at about 120°, and having a radially inward surface forcontacting the guide pin 27. In addition, between the ridges 50-1, 50-2and 50-3 there may be provided intervening grooves 52-1, 52-2 and 52-3,offset circumferentially from one another at about 120°. Across-sectional view taken through a guide pin hole 25 is represented inFIG. 4A.

As represented in FIG. 5, and shown in detail in FIG. 12B, theconfiguration of ridges and grooves in one ferrule housing 210A may bearranged in opposition to the configuration of ridges and grooves in theabutting ferrule housing 210B so that the ridges of one housing alignwith the grooves of the other housing. This is represented by the endview shown in FIG. 12B, taken in a direction of arrow X in FIG. 5,wherein the ridges 50-1B, 50-2B and 50-3B of the housing 210B arevisible at the ends of the grooves 52-1A, 52-2A and 52-3A of the housing210A. The circumferential (angular) length of the ridges 50-1, 50-2 and50-3 may be at most about 60°, and the circumferential (angular) lengthof the grooves 52-1, 52-2 and 52-3, may be at least about 60°. In anembodiment, the angular length of the grooves should be greater than theangular length of the ridges so that when mated the ridges of oneferrule do not overlap with the ridges of the mating ferrule at theedges of the ridges.

Since it may be common with some ferrules, as shown in FIG. 5, toconnect ferrules by inverting one ferrule housing 210A of one cableconnector in relation to the other ferrule housing 210B to which it isto be connected, a configuration of ridges and grooves, such as isillustrated in FIGS. 4B, 4C and 5 may provide for such an oppositionalignment. Referring to FIG. 4B, for example, guide pin holes 25 mayeach have a groove 52 disposed upwardly, and therefore, when inverted,an additional housing will have the same groove disposed downwardly.

With such a fluted configuration of guide pin holes 25, any accumulatedforeign material that occurs on the connection surface 216 at the baseof a guide pin 27 will thereby end up, when adjoining an adjacentferrule, in a groove 52 of the guide pin hole of the adjacent ferrule.This is represented in FIGS. 13A-13C, depicting a connection of ferrulesby means of an alignment guide pin 27. In the depiction as shown,ferrule housing 210A has a groove 52A at the top and a ridge 50A at thebottom, while the inverted ferule housing 210B has a ridge 50B at thetop and a groove 52B at the bottom. Guide pin 27, previously insertedinto housing 210A, as shown in FIG. 13A, has foreign material particles60 on the surface, with an accumulation of particles 60-1 on theconnection surface 216A at the base of the pin 27.

As represented in FIG. 13B, as the housing 210B is inserted onto theguide pin 27, the upper ridge 50B of the guide pin holes pushes theforeign material particles 60-2 along the guide pin in a direction tothe left in the figure toward the opposite housing 210A, while anyforeign material 60-3, on the bottom side remains in place within thelower groove 52B. When connection surfaces 216A and 216B abut, particles60-2 are pushed into the opposing groove 52A, while the particles 60-1likewise enter into an opposing groove 52B, thereby allowing for thesurfaces 216A and 216B to cleanly abut one another, resulting in reducedinsertion loss and return loss, and thereby resulting in reduced networkfailures.

In alternative embodiments, the number and configuration of ridges andgrooves may vary. For example, as shown in FIG. 14, an internal flutingwithin the guide pin holes 25 may include fours ridges 53 separated byfour grooves 55, also configured so that when one housing is invertedfor mating the ridges align with grooves of an opposing housing.Alternatively, there may be five ridges/five grooves, six ridges/sixgrooves, seven ridges/seven grooves or eight ridges/grooves, or anyconfiguration of ridges and grooves that may be accommodated by theinternal dimensions of the guide pin holes. In general, the pin holes 25may have n longitudinal ridges separated by n longitudinal grooves. Then longitudinal ridges may be disposed equidistantly from one another onthe interior surface and spaced at 360°/n from one another along theinternal circumference of the pin hole, and each ridge may extend in acircumferential direction at most about 360°/2n along the internalcircumference of the pin holes. Similarly, the n longitudinal groovesmay be disposed equidistantly from one another on the interior surfaceand spaced at 360°/n from one another along the internal circumferenceof pin hole, and each groove may extend in a circumferential directionat least about 360°/2n along the internal circumference of the pinholes.

This disclosure is not limited to the particular systems, devices andmethods described, as these may vary. The terminology used in thedescription is for the purpose of describing the particular versions orembodiments only, and is not intended to limit the scope.

In the above detailed description, reference is made to the accompanyingdrawings, which form a part hereof. In the drawings, similar symbolstypically identify similar components, unless context dictatesotherwise. The illustrative embodiments described in the detaileddescription, drawings, and claims are not meant to be limiting. Otherembodiments may be used, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presentedherein. It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in thefigures, can be arranged, substituted, combined, separated, and designedin a wide variety of different configurations, all of which areexplicitly contemplated herein.

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its spirit and scope, as will be apparentto those skilled in the art. Functionally equivalent methods andapparatuses within the scope of the disclosure, in addition to thoseenumerated herein, will be apparent to those skilled in the art from theforegoing descriptions. Such modifications and variations are intendedto fall within the scope of the appended claims. The present disclosureis to be limited only by the terms of the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isto be understood that this disclosure is not limited to particularmethods, reagents, compounds, compositions or biological systems, whichcan, of course, vary. It is also to be understood that the terminologyused herein is for the purpose of describing particular embodimentsonly, and is not intended to be limiting.

As used in this document, the singular forms “a,” “an,” and “the”include plural references unless the context clearly dictates otherwise.Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art. Nothing in this disclosure is to be construed as anadmission that the embodiments described in this disclosure are notentitled to antedate such disclosure by virtue of prior invention. Asused in this document, the term “comprising” means “including, but notlimited to.”

While various compositions, methods, and devices are described in termsof “comprising” various components or steps (interpreted as meaning“including, but not limited to”), the compositions, methods, and devicescan also “consist essentially of” or “consist of” the various componentsand steps, and such terminology should be interpreted as definingessentially closed-member groups.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations). Furthermore, in thoseinstances where a convention analogous to “at least one of A, B, and C,etc.” is used, in general such a construction is intended in the senseone having skill in the art would understand the convention (e.g., “asystem having at least one of A, B, and C” would include but not belimited to systems that have A alone, B alone, C alone, A and Btogether, A and C together, B and C together, and/or A, B, and Ctogether, etc.). In those instances where a convention analogous to “atleast one of A, B, or C, etc.” is used, in general such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, or C” wouldinclude but not be limited to systems that have A alone, B alone, Calone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). It will be further understood by those withinthe art that virtually any disjunctive word and/or phrase presenting twoor more alternative terms, whether in the description, claims, ordrawings, should be understood to contemplate the possibilities ofincluding one of the terms, either of the terms, or both terms. Forexample, the phrase “A or B” will be understood to include thepossibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” and the like include the number recited andrefer to ranges which can be subsequently broken down into subranges asdiscussed above. Finally, as will be understood by one skilled in theart, a range includes each individual member. Thus, for example, a grouphaving 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, agroup having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells,and so forth.

Various of the above-disclosed and other features and functions, oralternatives thereof, may be combined into many other different systemsor applications. Various presently unforeseen or unanticipatedalternatives, modifications, variations or improvements therein may besubsequently made by those skilled in the art, each of which is alsointended to be encompassed by the disclosed embodiments.

What is claimed is:
 1. An optical fiber connector configured for beingcoupled with an adapter to mate with another optical fiber connector,the connector comprising: a housing comprising a first end for beingcoupled with the adapter, the housing defining a first longitudinalpassage therethrough, the first longitudinal passage defining a firstlongitudinal axis; a ferrule floatably mounted at the first housing endwithin the first longitudinal passage for relative movement between theferrule and the housing, the ferrule comprising: a first end protrudingforward of the first housing end, and a second end spaced from the firstend and disposed within the first longitudinal passage, the ferruledefining a second longitudinal axis extending from the first end to thesecond end, and the first end comprises an end face for mating with anend face of an additional ferrule; and at least one side wall having afirst wall end at the end face and extending from the end face to asecond wall end adjacent the second end of the ferrule, the at least oneside wall tapering outwardly away from the second longitudinal axis in adirection from the end face towards the second end.
 2. The connector ofclaim 1, wherein the ferrule is tiltable within the housing passage tooffset the second longitudinal axis with respect to the firstlongitudinal axis.
 3. The connector of claim 1, wherein the at least oneside wall comprises a first side wall, a second side wall, a third sidewall and a fourth side wall disposed about the second longitudinal axisand each extending from a first wall end at the end face to a secondwall end adjacent the second end of the ferrule, wherein the first sidewall and the third side wall are disposed opposite one another and thesecond side wall and the fourth side wall are disposed opposite oneanother and orthogonal to the first side wall and the third side, andeach side wall is independently disposed at a taper angle with respectto the second longitudinal axis.
 4. The connector of claim 3, wherein:the first side wall, the second side wall, the third side wall and thefourth side wall define a rectangular frustum having a firstcross-sectional area defining the end face and a second cross-sectionalarea at the second wall ends, wherein the second cross-sectional area isgreater than the first cross-sectional area; each of the first sidewall, the second side wall, the third side wall, and the fourth sidewall are disposed at the same taper angle with respect to thelongitudinal axis; and the ferrule is tiltable within the firstlongitudinal passage of the housing through a conical deflection aboutthe first longitudinal axis to offset the second longitudinal axis withrespect to the first longitudinal axis by an amount of at least thetaper angle.
 5. The connector of claim 4, wherein: the second end of theferrule comprises a flange adjacent the second wall ends, the flangeextending laterally away from the second walls ends to define aperipheral shoulder adjacent the second wall ends, the flange defining athird cross-sectional area greater than the second cross-sectional area;the housing passage comprises a first passage portion at the firsthousing end and a second passage portion adjacent the first passageportion, wherein: the first passage portion comprises an interiorsurface disposed about at least a portion of the ferrule, the interiorsurface comprising a first surface adjacent the first side wall, asecond surface adjacent the second side wall, a third surface adjacentthe third side wall, and a fourth surface adjacent the fourth side wall,with the first surface, the second surface, the third surface and thefourth surface each parallel to the first longitudinal axis; the firstside wall, the second side wall, the third side wall and the fourth sidewall define a rectangular passage having a shape corresponding to thesecond cross-sectional area of the ferrule, and the first passageportion has a cross-sectional area greater than the second crosssectional area and less than the third cross-sectional area; and thesecond passage portion has a cross-sectional area greater than the thirdcross-sectional area to define an internal shoulder extending around theinterior surface between the first passage portion and the secondpassage portion; and the ferrule fits within the housing passage withthe first end of the ferrule extending through the first passage portionand the ferrule flange in the second passage portion; and the connectorfurther comprises a biasing device for biasing the peripheral shoulderof the ferrule flange into engagement with the internal shoulder.
 6. Theconnector of claim 5, wherein at least one of the peripheral shoulder ofthe ferrule flange and the internal shoulder of the passage comprises abeveled corner for engaging the other of the internal shoulder and theperipheral shoulder for centering the ferrule within the first passageportion under bias of the biasing device.
 7. The connector of claim 3,wherein: the connector is an MPO connector; the ferrule comprises an MTferrule; the taper angle is about 3°; and the ferrule additionallycomprises at least first and second alignment pin holes extendingthrough the housing from the end face to the second end, and configuredfor receiving an alignment pin therein, each of the first and secondalignment pin holes having a longitudinal direction parallel with thelongitudinal axis, and each pin hole defining an interior surfacecomprising a plurality of spaced apart longitudinal grooves extendingfrom the end face.
 8. The connector of claim 7, wherein the interiorsurface within each of the first and second alignment pin holescomprises at least three longitudinal ridges spaced at about 120° fromone another about the internal circumference of the pin holes, with thelongitudinal ridges extending in a circumferential direction at mostabout 60° along the internal circumference of the pin holes, and thelongitudinal grooves disposed between the longitudinal ridges extend atleast about 60° along the internal circumference of the pin holes.
 9. Anoptical fiber connector configured for being coupled with an adapter tomate with another optical fiber connector, the connector comprising: ahousing comprising a first end for being coupled with the adapter, thehousing defining a first longitudinal passage therethrough, the firstlongitudinal passage defining a first longitudinal axis; a ferrulefloatably mounted at the first housing end within the first longitudinalpassage for relative movement between the ferrule and the housing, theferrule comprising: a first end protruding forward of the first housingend, and a second end spaced from the first end and disposed within thefirst longitudinal passage, the ferrule defining a second longitudinalaxis extending from the first end to the second end, and the first endcomprises an end face for mating with an end face of an additionalferrule; and at least first and second alignment pin holes in the endface configured for receiving an alignment pin therein, each of thefirst and second alignment pin holes having a longitudinal directionparallel with the second longitudinal axis, and each pin hole definingan interior surface comprising a plurality of spaced apart longitudinalgrooves extending from the end face and into the ferrule.
 10. Theconnector of claim 9, wherein the interior surface within each of thefirst and second alignment pin holes comprises at least threelongitudinal ridges spaced at about 120° from one another about theinternal circumference of the pin holes, with the longitudinal ridgesextending in a circumferential direction at most about 60° along theinternal circumference of the pin holes, and the longitudinal groovesdisposed between the longitudinal ridges extend at least about 60° alongthe internal circumference of the pin holes.
 11. The connector of claim9, wherein the interior surface within each of the first and secondalignment pin holes comprises at least two longitudinal ridges spacedcircumferentially from one another about the internal circumference ofthe pin holes, and separated from one another by one of the plurality oflongitudinal grooves, with each of the at least two longitudinal ridgesdefining an interior surface for contacting an alignment pin to bedisposed within the pin hole.
 12. The connector of claim 11, wherein:the interior surface for contacting an alignment pin define a firstinternal diameter within the pin hole and the longitudinal grooves havea base defining a second internal diameter within the pin hole; thesecond internal diameter is greater than the first internal diameter;and the first internal diameter corresponds to a diameter of analignment pin to be disposed within the pin hole.
 13. The connector ofclaim 12, wherein: the pin holes have n longitudinal ridges separated byn longitudinal grooves; the n longitudinal ridges are disposedequidistantly from one another on the interior surface and spaced at360°/n from one another along the internal circumference of pin hole,and each ridge extends in a circumferential direction at most about360°/2n along the internal circumference of the pin holes; and the nlongitudinal grooves are disposed equidistantly from one another on theinterior surface and spaced at 360°/n from one another along theinternal circumference of pin hole, and each groove extends in acircumferential direction at least about 360°/2n along the internalcircumference of the pin holes.
 14. The connector of claim 13, wherein:the ferrule comprises an MT ferrule; n is three; the longitudinal ridgesare disposed at about 120° from one another and extend in acircumferential direction at most about 60° along the internalcircumference of the pin holes; the longitudinal grooves disposedbetween the longitudinal ridges extend at least about 60° along theinternal circumference of the pin holes; the housing further comprises afirst side wall, a second side wall, a third side wall and a fourth sidewall disposed about the second longitudinal axis and each extending froma first wall end at the end face to a second wall end adjacent thesecond end, wherein the first side wall and the third side wall aredisposed opposite one another and the second side wall and the fourthside wall are disposed opposite one another and orthogonal to the firstside wall and the third side, and each side wall is disposed at a taperangle of about 3° with respect to the second longitudinal axis; the pinholes are disposed adjacent the second and fourth side walls and have atop disposed towards the first side wall and a bottom disposed towardsthe third side wall; and each pin hole has one of the three grooves atthe top and one of the three ridges at the bottom.
 15. The connector ofclaim 11, wherein: the ferrule is configured to be mated with anadditional optical ferrule with the end face of the ferrule inface-to-face contact with the end face of the additional opticalferrule; and the longitudinal ridges and longitudinal grooves withineach pin hole of the ferrule are configured so that when mated, thelongitudinal ridges of the ferrule are aligned with the longitudinalgrooves of the additional optical ferrule, and the longitudinal groovesof the ferrule are aligned with the longitudinal ridges of theadditional optical ferrule.